The term “time-of-flight camera system” is meant to encompass not only systems that measure distances directly from the time of flight (TOF) but also and especially all time-of-flight camera systems or 3D-TOF camera systems that acquire time-of-flight information from the phase shift of emitted and received radiation. Particularly well-suited time-of-flight cameras or 3D-TOF cameras are PMD cameras with photonic mixer devices (PMD) of the type described, among others, in European patent application EP 1 777 747, U.S. Pat. No. 6,587,186 and German patent application DE 197 04 496, and commercially available, for example, from the “ifm electronic gmbh” company under the name Frame Grabber O3D. In particular, a PMD camera allows a flexible arrangement of the light source and of the detector, which can be arranged in a housing as well as separately. It goes without saying that the terms “camera” or “camera system” also include cameras or devices that have at least one receiving pixel such as, for instance, the O1D distance sensor made by the applicant.
German patent application DE 10 2004 044 581 A1 likewise discloses a method and a device for the time-of-flight-sensitive measurement of a signal in which the phase and the amplitude of an intensity-modulated input signal are determined. The input signal is mixed with a first reference signal, whereby the phase of the signal is subsequently determined by means of an IQ process employing an odd and even autocorrelation function.
German patent application DE 10 2004 016 625 A1 discloses a PMD system for receiving and processing modulated electromagnetic signals in which a semiconductor is configured to receive and convert electromagnetic radiation into an electric measured quantity. The semiconductor has an input for a modulated signal as well as at least two accumulation electrodes that are connected to an output electronic unit and at whose output a mixture of the received signal and of a modulation signal is provided as an electric signal.